1. Field of the Invention
This invention relates to an improved very low spring rate, vibration-damping clutch and pinion assembly particularly adaptable for use with heavy-duty, high torque rise, slow-speed engines.
2. Prior Art
The high torque rise, slow speed engines currently in use on heavy-duty trucks and otherwise in industry, produce torsional impulses which are sufficient to put the power train in resonance at engine operating speeds. Resonance within an engine's operating speed is highly undesirable as it causes clutch wear, loss of power and vibration such that vibration can be actually felt even by the driver of the truck. Accordingly, various measures have been taken to prevent resonance of the power train within the operating speed of the engine.
One such prior art measure is to add inertia to the drive line. This has been done in Mack trucks by adding a drive line fly wheel before the input to the driven axle or behind the transmission. A drive line flywheel could also be used in combination with a vibration damping clutch. However, adding a drive line flywheel is not the most desirable solution to the problem as it adds extra weight, and causes problems of access and appearance.
Another approach to the problem is the use of a vibration-damping clutch. One vibration-damping clutch is disclosed in U.S. Pat. No. 4,254,855 granted Mar. 10, 1981. However, this clutch with only a single row of coaxial spring dampers cannot be made to have a sufficiently low spring rate to adequately provide the required damping effect for some engines. In order to minimize or prevent the spring dampener from bottoming out they often have dampers so stiff that they act as torque peak clippers and not vibration controllers.
Accordingly, there is a significant need in the art for a very low spring rate vibration-damping assembly which does not utilize added inertia weights or extra bulky components.